The present invention relates to a method for operating a pharmacy order-picking device. In a modern pharmacy order-picking device, smooth and automatic storage and retrieval are essential for the efficiency of the installation. Positioning deviations of a control appliance (20), for example caused by mechanical wear, jeopardize smooth operation of the installation, since a precise positioning needed for storage or retrieval is no longer achieved. The present method reduces the susceptibility of the pharmacy order-picking device to disruption. To detect a positioning deviation of the control appliance (20) in the horizontal direction, at least one desired value of at least one reference position is made available, the control appliance (20) is brought to a position corresponding to the desired value in the horizontal direction and, when a signal characteristic of a reference position is detected, an actual value of this reference position is determined. A desired value is then compared with a corresponding actual value, or two actual values are compared with each other, and a deviation is determined. If a deviation is determined that exceeds a limit value, a signal pointing to the need for a correction is output. Depending on the deviation, automatic correction of the position deviation can be performed.